This application claims the priority of 199 56 375.6, filed Nov. 24, 1999, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a flame colorant additive for methanol for the operation of a fuel cell system.
It is known to use methanol as a hydrogen source for the operation of fuel cell systems. Since methanol burns substantially colorless, additives are desirable, especially in the use of fuel cell systems in motor vehicles.
U.S. Pat. No. 4,932,979 discloses the use of flame colorant additives. Accordingly, methanol is treated with flame colorant additives and lubricants which permit the complete combustion of the methanol with minimal residues and low pollutant content. In the reformation of methanol, and also in other processes in the fuel cell system, however, catalysts are used which are adversely affected by even small amounts of foreign substances. For this reason, only methanol of a very high purity is used in fuel cell systems.
PCT/EP/99/07662 discloses providing methanol with an additive from a reservoir, which in case of an accident will cause flame coloration. Thus the catalysts used in the fuel cell system will not necessarily be adversely affected by additives in the methanol, since the addition is made only in case of an accident, it being assumed that the damage due to the accident is greater than catalysts contaminated or rendered useless by the accident.
The problem of the present invention is to provide a hydrogen-containing fuel for fuel cells which is suitable for the operation of fuel-cell vehicles and which has a sufficient flame coloration.
According to the present invention, a hydrogen carrier, preferably methanol, is used as a hydrogen-containing fuel treated with a catalyst-neutral flame colorant additive.
Preferably an acetate, and with special preference sodium acetate, is added. This additive produces a definite flame coloring. At the same time, no negative effect on the catalyst materials is to be seen, especially the catalysts used in the reforming of methanol. This permits the addition of the flame colorant additive during normal operation.
Further advantages and embodiments of the invention will appear from the additional claims and the description.